1. Field of the Invention
This invention relates to a photographic light-sensitive material having improved processing properties and improved surface properties, and more particularly, it is concerned with a novel photographic light-sensitive material which is capable of forming rapidly a photographic image of good quality with a photographic processing at a high temperature and which has excellent adhesion resistance.
2. Description of the Prior Art
In photographic light-sensitive materials, in general, gelatin, other hydrophilic natural high molecular weight materials and/or hydrophilic synthetic high molecular weight materials are contained in silver halide emulsion layers, photographic auxiliary layers such as intermediate layers, protective layers and antihalation layers or undercoated layers between these layers and supports. Photographic light-sensitive materials containing these hydrophilic high molecular weight materials are ordinarily processed with various aqueous solutions differing in pH, salt concentration and liquid temperature in the steps of developing, stopping, fixing, water washing and bleaching in the case of color photographic materials, after exposure, to thus form photographic images.
When the processing temperature is higher as in the case of a rapid processing of a photographic light-sensitive material (operation for forming an image by carrying out development or other photographic processings rapidly) or when a number of processings for various purposes are carried out for a long time as in the case of a reversal color photographic material, many disadvantages are unavoidable in that the photographic light-sensitive emulsion layers and other layers swell and soften too much, resulting in a reduction of the physical strength or an occurrence of net patterns called "reticulation" on the surface.
These phenomena markedly reduced the commercial value of photographic light-sensitive materials regardless of whether they are black-and-white light-sensitive materials or color light-sensitive materials, and, therefore, these phenomena should be avoided. Recently, processing methods for photographic light-sensitive materials have been enlarged. For example, it has been required to increase the productivity in photographic processings by carrying out a processing at a high temperature such as 30.degree. C., 38.degree. C. or 50.degree. C., not at room temperature (e.g., 20.degree. .about. 25.degree. C.) in the prior art, and thereby decreasing the time for the processing. As a technique capable of satisfying such a requirement, incorporation of a hardener in an amount of several times to several tens of times the conventional amount previously employed in a photographic light-sensitive emulsion layer or protective layer in the production of photographic light-sensitive material so as to impart sufficient physical strength to resist the severe processing conditions has been considered. According to this method, however, occurrence of reticulation can be prevented to some extent. However, a complete prevention is not possible and, rather, a phenomenon known as "after-hardening" tends to occur, such that, during storage of a photographic light-sensitive material, the physical strength of the emulsion film deteriorates gradually, thus resulting in difficulty in maintaining the photographic quality. Furthermore, this method has a disadvantage that a photographic layer is hardened to such a large extent that permeation or diffusion of a developer during development is hindered and the sensitivity is substantially reduced.
Other methods have been proposed in which a photographic material after exposure is treated with an aqueous solution containing a hardener, called a "pre-hardening bath", immediately before development, or development and hardening are simultaneously carried out using a developer containing a hardener. However, these methods have also the disadvantages that, depending on the types of hardeners used, unfavorable results are produced, for example, fog, deterioration of photographic properties and color contamination in the case of color photographic materials. Moreover, the types of hardeners and sensitive materials which can be used and the processing conditions should be limited to a narrow range in order to obtain photographic layers having the required physical strength in a short time without deteriorating the photographic properties. Above all, the method using a prehardening bath is not considered to be suitable for the purpose of decreasing the photographic processing time and facilitating the processing because the number of steps is increased.
As a further method for suppressing the occurrence of reticulation, application of carboxymethylated casein or ethyl cellulose sulfate sodium salt previously to the uppermost layer of a photographic light-sensitive material on the emulsion side instead of a gelatin protective layer has been reported (U.S. Defensive Publication T 887,012). This method is considered to be an advantageous method since it is not necessary to add a large amount of hardener to a photographic layer. However, carboxymethylated casein has a disadvantage that not only impurities contained therein, adversely influencing the photographic property, are difficult to remove, but also the aqueous solution thereof is difficult to coat onto an emulsion layer to form a uniform layer. Furthermore, ethyl cellulose sulfate sodium salt is not always suitable for use as a raw material in the production of a photographic light-sensitive material, since it is difficult to prepare the salt having a good solubility in water with a good reproducibility and storage stability over a long period of time, and the setting property when cooled after coating and coating property are not good as would be somewhat predicted from a consideration of the chemical structure of the sulfuric acid ester.
On the other hand, silver halide photographic materials generally have a surface layer containing a hydrophilic colloid such as gelatin as a binder. Therefore, the surface of the photographic material exhibits an increased adhesiveness or tackiness in an atmosphere of high humidity, in particular, high humidity and high temperature, and tends to adhere easily to other materials. This phenomenon of adhesion takes place often between photographic materials or between a photographic material and other materials during production, photographing, processing, projection or storage, often resulting in accidents.
In order to solve this problem, incorporation in a surface layer of fine particles of an inorganic substance such as silicon dioxide, magnesium oxide, titanium dioxide or calcium carbonate or an organic substance such as polymethyl methacrylate or cellulose acetate propionate, having a particle size of about 0.3 to 5 microns in diameter, to increase the roughness of the surface or to matt the surface, thus decreasing the adhesiveness of the surface, is well known in the art. In the practice of this method, however, there are disadvantageous side effects since a uniformly coated layer is not obtained due to aggregation in the coating liquor containing such a substance, a photographic material tends to be scratched due to its low slippage properties, the motion of a film in a camera or a projector is disturbed, the transparency of the image formed is reduced and the graininess of the image is deteriorated. Therefore, it has hitherto been desired to improve the adhesion resistance of a photographic material without these disadvantageous side effects.
As described above, reticulation and adhesion are very important problems in the photographic industry, but it is difficult to solve simultaneously these two problems using prior art methods.